#include <iostream>
#include <vector>
#include <string>
int main (int argc, char *argv[])
{
    int n_test=0;
    std::string dump;
    double time=0;
    double total_time=0;
    while (true){
	if (!(std::cin>>dump))
	    break;
	std::cin >> time;
	total_time+=time;
	n_test++;
}
    std::cout << "average time: " << total_time/n_test << std::endl;
    return 0;
}
